The watering of fowl and other animals involves waterers of advanced design immediately responsive to demands of the animal without excessive release of water. Such systems are operated at low pressures and a typical system involves a multiplicity (hundreds--thousands) of individual waterer cups and each with its control valve. Valve controlled waterer cups of the type under consideration are self-cleaning by utilizing the animal habits to advantage in cooperation with the waterer structure; and in general such systems are highly satisfactory. However, the water pressure is relied upon for effecting the normal valve closures and in the event of total loss of pressure in the water supply, difficulties arise in reinstating system operation. That is, extensive waterer systems will not build up sufficient pressure in the relatively short length of time required before flooding will occur, and in some instances might never build up pressure because of the total open condition. Therefore, in the event of a catastrophe or power failure due to storms, etc. and beyond human control, extensive waterer systems of the type under consideration must be shut down and restarted, and all of which is time consuming and can occur when man power is not available. Therefore, it is an object of this invention to provide means by which each individual waterer is protected against flooding by providing a float control for the valve thereof.